A large portion of the Las Vegas Valley within a 10-mile (16 km) radius of the plant was affected and several agencies activated disaster plans.

[5] With the Space Shuttle fleet grounded as a result of the Challenger disaster two years prior, there was United States Government instruction that excess perchlorate – to be used for future Shuttle boosters and which was owned by the U.S. Government or its prime contractors – would be stored in customer-owned aluminum bins as customer-owned material at the PEPCON plant.

The United States Department of Labor (USDOL), working with the Division of Occupational Safety and Health (DOSH), issued a lengthy report on the accident that discounted the cause and origin findings of the CCFD.

USDOL noted that the Arson Division of CCFD maintained control over the site for several weeks and that DOSH and PEPCON investigating teams were not permitted entry into the facility until 13 days after the event.

The USFA report stated that this activity caused a fire that spread rapidly in the fiberglass material, accelerated by nearby ammonium perchlorate residue.

[4][9] USFA[4] reported that the first of a series of explosions occurred in the drums about 10 to 20 minutes after ignition, and employees had begun fleeing on foot or in cars.

USDOL reported this differently, stating that the fire spread rapidly to the north side of the partition, northeast and south walls by radiative and convective heat transfer.

USDOL reported that six or seven detonations occurred solely in areas where aluminum econo bins or steel drums were utilized to store the product of nominal 200 micron size.

[9] USFA reported that little fuel remained after that, causing the flame to diminish rapidly, except for a fireball that was supplied by the high-pressure natural gas line underneath the plant, which had been ruptured by one of the explosions.

[9] About 75 people escaped successfully, but two were killed in the last two larger explosions: Roy Westerfield, PEPCON's controller, who stayed behind to call the CCFD; and Bruce Halker, the plant manager, who stood near his car when the first major detonation occurred.

As he approached the plant, he could see a massive white and orange fireball about 100 ft (30 m) in diameter and dozens of people fleeing the scene.

[4] At about 11:54, as he approached the site, the first of the two major explosions sent a shock wave that shattered the windows of his car and showered him and his passenger with glass.

[4] The second major explosion nearly destroyed the chief's car; after he and his passenger were cut by flying glass, he was able to drive the damaged vehicle to a hospital.

Roads in the area were clogged in both directions due to residents trying to leave and curious spectators headed toward the scene, creating a traffic jam that took over two hours to clear.

Crews in protective clothing headed to the scene to clean up, a slow process due to leaking tanks of anhydrous ammonia and residue from acids and other products.

[4] An investigation estimated that the larger explosion was equivalent to 0.25 kiloton of TNT, approximately the same yield of a tactical nuclear weapon.

[6][12] After the incident, American Pacific Corporation changed the name of the perchlorate chemicals manufacturing subsidiary to PEPCON Production, Inc and within one year, to Western Electrochemical Co.

[6] It built a new ammonium perchlorate plant in an isolated area about 14 miles (23 km) outside of Cedar City, Utah with a substantial voluntary no-build buffer around it.

Natural gas service to this WECCO facility is handled in a different manner (mostly above ground away from AP storage areas) than was the case at PEPCON.